1. Field of the Invention
The present invention generally relates to circular knitting machines and more particularly a roll feed for such machines in which yarn being fed from supply cones to the needles is maintained under constant tension between the roll feed and needles.
2. Description of the Prior Art
The feeding of strands of yarn to the knitting mechanism in a knitting machine, such as a circular knitting machine, has presented substantial problems in view of the non-uniformity of the yarn on the supply cones. For example, if the yarn is too tightly wound on the cone, it sometimes is difficult to unwind and, in effect, sticks to the cones thus resulting in excessive tension in the strands between such sticking cones and the needle receiving the strand of yarn therefrom. In other instances, the yarn on the cone may be underwound so that too little tension exists in the strand between the cone and needle. Non-uniform tension in the yarn strands results in a non-uniform fabric. This problem has been recognized in the knitting industry and efforts have been made to solve the problem. One example of such efforts is disclosed in prior U.S. Pat. No. 3,243,974, issued Apr. 5, 1966, in which a pair of side-by-side rollers receive the yarn strands therebetween with one of the rollers being spring biased toward the other in an effort to exert tension on the yarn strands which pass between the rollers to the needles. Other prior patents relating to this invention are U.S. Pat. Nos.:
424,295 FILED ON Mar. 25, 1890;
1,947,958 FILED ON Feb. 20, 1934;
2,111,984 FILED ON Mar. 22, 1938;
3,080,837 FILED ON Mar. 12, 1963;
3,693,378 FILED ON Sept. 26, 1972.
While such previous devices have operated with some degree of success, uneven yarn tension remains a problem in circular knitting machines even when conventional tape feed arrangements are employed or arrangements such as disclosed in the prior patents are employed.